Originally Posted by
Mitch R
What you have is the 4t60, with electronic torque converter lockup. Your transmission shifts on its own without input from the computer, except for torque converter lockup. Definitely sounds like it needs a rebuild unfortunately. If that's not an option, a transmission from a w-body car, which are grand prix, regal, lumina, and cutlass supreme from 90 to 93 sound work. 94 and up went to the 4t60-e, which will not work as it needs the computer to command gear changes.